Power Trim Ram Cylinder O-Ring Seal Kit – Fits MerCruiser Alpha One, Gen II, Bravo & R/MR Drives (Replaces 25-87400A2)

Power Trim Ram Cylinder O-Ring Seal Kit – Fits MerCruiser Alpha One, Gen II, Bravo & R/MR Drives (Replaces 25-87400A2)

This comprehensive seal kit provides all the necessary components to rebuild one power trim ram cylinder for a wide range of Mercury/MerCruiser stern drives. It is designed to restore hydraulic integrity and prevent fluid leaks in your trim system.

This kit is a direct replacement for sterndrive models including Alpha One (Gen I & II), Bravo I, Bravo II, Bravo III, R, and MR drives, ensuring a precise fit and reliable performance.

• Direct Installation: Engineered to replace OEM and aftermarket equivalents without modification.
• Complete Kit: Includes all required synthetic rubber o-rings and seals to fully service one trim cylinder.
• Material: High-quality synthetic rubber for durability and resistance to hydraulic fluid and marine environments.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

This kit includes all necessary seals to rebuild ONE trim cylinder for your sterndrive.

• A full set of various synthetic rubber O-rings and seals for a complete rebuild.

Installation Guide

Professional installation is recommended. The general steps for replacing the trim cylinder seals are as follows:

1. Prepare the Sterndrive: Safely secure the vessel and support the sterndrive in the fully raised position using a drive lock or brace.
2. Remove Cylinder: Disconnect the hydraulic lines, being careful to manage any fluid spillage. Remove the pivot pins to detach the trim cylinder from the sterndrive housing.
3. Disassemble Cylinder: Carefully remove the end cap or gland from the cylinder body. Specialized tools may be required to avoid damaging the components.
4. Extract Old Seals: Remove the piston rod assembly from the cylinder body. Carefully take off all old O-rings and seals from both the piston and the end cap.
5. Clean & Inspect: Thoroughly clean all metal parts with a suitable solvent and inspect for any scratches, corrosion, or damage. Ensure the cylinder bore is smooth.
6. Install New Seals: Lubricate the new seals from the kit with hydraulic fluid and carefully install them in their respective grooves on the piston and end cap.
7. Reassemble Cylinder: Re-insert the piston assembly into the cylinder body and reinstall the end cap, torquing it to the manufacturer's specification.
8. Reinstall Cylinder: Mount the rebuilt cylinder back onto the sterndrive assembly and reconnect the hydraulic lines.
9. Bleed the System: Fill the hydraulic reservoir and cycle the trim system up and down several times to bleed any air out of the system. Check fluid levels again.
10. Final Check: Test the trim for smooth operation and check thoroughly for any hydraulic fluid leaks around the seals and fittings.

Troubleshooting & FAQ

Q: How do I know if this seal kit will fit my sterndrive?
A: This kit is designed for a wide range of MerCruiser sterndrives, including Alpha One (Gen I & II), Bravo I/II/III, R, and MR models. It is a direct replacement for OEM part number 25-87400A2 and aftermarket parts like Sierra 18-2649. Always check your service manual or original part number to confirm compatibility before ordering.

Q: What are the main signs my trim seals are failing and need replacement?
A: Common symptoms include visible hydraulic fluid leaks around the cylinder rods or fittings, the sterndrive slowly "drifting" down from the trimmed position, or a slow, weak, or "spongy" response when operating the power trim.

Q: Is this kit enough to service my entire trim system?
A: This kit contains all the seals required to rebuild one single power trim cylinder. Most sterndrive applications have two cylinders, so if you plan to service both, you will need to purchase two kits.

Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.